The European space probe “Euclid”, which will be launched on Saturday from Cape Canaveral in the US state of Florida, is trying to unravel one of the most important mysteries represented by two mysterious dark objects that make up 95 percent of astronomy. universe, but no data is available on their exact nature.

The European Space Agency (ESA) mission will launch on Saturday at 15:11 GMT on a Falcon 9 rocket manufactured by SpaceX.

The two-tonne probe, designed by Thales Alenia Space, will be launched to its final destination 1.5 million km from Earth. From there, Euclid, named after the discoverer of geometry, would draw a three-dimensional map of the universe, including two billion galaxies covering more than a third of the universe.

The third dimension of the map will be time: by capturing the light that took up to ten billion years to reach us from galaxies, Euclid will explore the distant past of the universe, which is 13.8 billion years old.

The goal is to reconstruct the history of the universe by dividing it into “time segments,” explained astrophysicist Yannick Millier, head of the 16-nation “Euclidean” Union, during a press conference.

The mission’s hope is that it will help reveal the traces left behind by dark matter and dark energy when galaxies formed.

Dark matter and dark energy are of unknown nature, but they rule the universe, which is only 5% made of “normal” visible matter. This lack of knowledge has been described by Giuseppe Rakka, head of the Euclid Mission, as a source of “cosmic dilemma”.

“Everything is happening so fast.”

Without this information, scientists cannot explain how the universe works. The history of the mystery dates back to the 1930s, when Swiss astronomer Fritz Zwicky, observing the Coma Cluster galaxy, assumed that much of its mass was invisible.

Almost 100 years later, the existence of this missing substance, described as black because it neither absorbs nor reflects light, has become unanimous. “When we look at the tip of the iceberg, there’s something we don’t understand: everything is going so fast,” says David Elbas, a member of the Euclid Union.

The rotation speed of the stars within galaxies, including our Sun, is so high that this material must be ejected from them, “like a rocket pulling itself away from Earth’s gravity,” the astrophysicist in the atom explained to AFP. Energy Commission. However, this substance exists, and therefore, according to Al-Baz, “we conclude that there is an additional weight that maintains it.”

In the late 1990s, astronomers discovered a second anomaly, on the scale of the entire universe, in which galaxies are rapidly moving away from each other under the influence of a repulsive force called dark energy.

This acceleration in the expansion of the universe is expected to have started about six billion years ago. By going back 10 billion years, Euclid could better observe and identify the first effects of dark energy, the hope of the mission.

“Astrophysics Gold Mine”

But how can the invisible be observed? By measuring its absence, it is through a twisting effect called gravitational lensing: light from a distant object, such as a galaxy, is invisibly deflected by the visible and dark matter it encounters as it returns to the point of observation.

“By subtracting visible matter, we can ‘calculate’ the presence of dark matter,” explains Giuseppe Rocca.

And David Elbas notes, “By looking at the path of these decays over the history of the universe, we can understand how dark energy works.”

The scientist compares it to a rubber balloon with lines drawn on it with a sign “to see how fast the balloon is inflated”, helping to understand the effects of dark matter. As for dark energy, it’s the breath that inflates a balloon.

The Euclid probe has two instruments on board: a visible light imager (VIS) and a near-infrared spectrophotometer (NISP).

According to Yannick Millier, this unprecedented mapping will be a “gold mine of astrophysics” because it allows us to study the shape of galaxies, the birth of clusters, black holes, and more.

It could help scientists finally catch the mysterious particles that make up dark matter that have eluded detection.

The €1.5 billion European project is expected to run until at least 2029.